Included in the scope are the following general types of classifier equipment:

• those using gas flow, as in air separators and cyclones;

• those using liquid flow, as in hydro cyclones and screws; and

• those using solid flow, as in screens.

It is intended that the scope of this procedure be limited to classification by size or shape, not including separation by type of material or composition. For example, some classifiers, including the gas-and liquid-flow types, separate based on interaction of inertial and drag forces, and inertia is affected by density. Thus materials of different density in mixture such as a crushed ore would separate at different sizes in such classifiers. These classifiers can make only a rough separation of such mixtures by either size or composition. They would separate purely by size only a material of uniform density, and by composition only a material of uniform size. Screens, on the other hand, separate primarily by a gauging action, relatively independent of density. See also Sect. 202.3.

This procedure is intended to be applied to particle size classification equipment as distinguished from particle collection equipment. The purpose of particle size classification is to separate particles by size; a collection system is designed to collect or recover as much particulate matter as possible from a gas or liquid stream irrespective of size. Many of the items discussed (especially sampling, particle size analysis and performance criteria), however, are also applicable to collection systems.

The major technical areas addressed herein are particle sampling, particle size measurement. And evaluation methodology.

This procedure will be useful to the engineer who intends to test and evaluate the performance of classifiers, Moreover, in providing a standard methodology and terminology, it should encourage the uniform and routine publication of usable performance data by equipment manufacturers, to aid equipment selection.

Purpose

The primary purpose of this procedure is to provide methodology for conducting and interpreting performance evaluation tests on particle classification equipment. Emphasis herein is directed toward the equipment user in assessing performance relative to that person's own application. See also Sect.301.0-Objective of Testing Classifiers.

Another purpose is to adopt terminology and nomenclature consistent with the tow major classifier application industries-namely, the chemical process and mining industries.